S()MK XOTI'.S ON TRin<;.\ll(>\ l\ CaI'K t'oMtw. 7!) 



Tlie following points may he noted t'l'oin tlie diagram: (1) The 

 rain falls chierty during the siiinmei* months. (2) The minimum is 

 zero for every month of the year, i.i'. the region to which the diagram 

 applies is one of di-oughts ; as an example, from April, 1902, to Decem- 

 ber, 1903, HO lain fell, and during the fourteen years in question 

 several droughts of eight to ten months' duration occurred. The run- 

 off from such a region will of course be Aery different from that of the 

 Table Mountain, llesults are not yet estaljlished with any accuracy, 

 but t)bser\ations on similar areas show that 10 per cent, may be looked 

 upon as a high run-off only to be expecte<l after phenomenal rains, 

 whilst anything less than 1 in. of rain in a day will give a run-oft' 

 varying from to 2 or 3 per cent, according to conditions of the 

 ground, itc. 2 to 3 per cent, would probably be as nuich as the total 

 average annual run-off would amount to. 



Lands. — The lands of the colony lie generally at a high altitude, 

 almost the whole surface, with the exception of a strip round the 

 coast, lying at from 2000 to 5000 feet above sea-level. The chief 

 geological formations represented in the colony are the Silurian, 

 Devonian and Carboniferous, Permian and Trias, and of these the 

 last named, repi'esented liy the Karroo system, covers the largest area 

 and gives the most fertile soil. 



Hivers. — The rivers of the colony are mostly intermittent, flowing 

 after rains, and then usually for a short time only. On the Karroo 

 the river channels are generally very deep, often 30 ft. or more below 

 the surface of the ground, which renders irrigation from them some- 

 what difficult. In the early days of the white occupation of the 

 country these channels in all probability did not exist, and rain falling 

 on the land flowed down to the plains, where it spread itself evenly 

 over the surface and was to a great extent absorbed by the soil, \ery 

 little water flowing away to the sea. As a consequence the plains 

 were generally covered with luxuriant \egetation, which provided food 

 and cover for all manner of game. 



Chancje in Physical Conditions. — Within recent times this con- 

 dition has changed. River channels have been formed, by which in 

 times of I'ain the water flows quickly away towards the sea, carrying 

 with it the easily disintegrated fertile silt of which the plains are 

 formed, whilst in times of drought the channel tends to drain away 

 all subsoil water and reduce the land to a parched condition. 



This change has been brought about partly by the trampling of 

 stock first forming a course for the water, which afterwards (juickly 

 developed into a deep channel. The burning- of the veld and the 

 construction of roads and railways have also no doubt contributed to 

 the result. To restore the land to its former condition and prevent the 

 sluiting of the soil, with the consequent rapid flow of the rain to the 

 sea, would mean untold wealth to the country. As already stated, 

 the rivers of the colony are mostly of an intermittent character, flow- 

 ing only perhaps a few times during the year, or they may be perennial 

 in the upper reaches and intermittent lower down. If such be the 

 case, the perennial water is generally used up before the river lias 



